Is there a performance difference between TextWriter.WriteLine(String)and TextWriteLine(String, arra

[Author]

I have always been wondering if there is any significant different
between doing

System.Console.WriteLine("Employee Name = " + employee.FirstName + " "
+ employee.LastName);

and

System.Console.WriteLine("Employee Name = {0} {1}",
employee.FirstName, employee.LastName);

Is it a matter of preference or is there a performance issue with the
first version rising from creating immutable strings through
concatenation?

Thank you.

 

[Jon Skeet [C# MVP]]

I have always been wondering if there is any significant different
between doing

System.Console.WriteLine("Employee Name = " + employee.FirstName + " "
+ employee.LastName);

and

System.Console.WriteLine("Employee Name = {0} {1}",
employee.FirstName, employee.LastName);

Is it a matter of preference or is there a performance issue with the
first version rising from creating immutable strings through
concatenation?

The first version is likely to be faster than the second. The first one
just calls string.Concat(string, string, string, string). The second
needs to parse the format string, work out the placeholders and then do
the concatenation.

However, all of this is likely to be dwarfed by the cost of actually
writing to the console. As always, write for readability first and if
you find there's a performance problem, measure, measure, measure!

 

[Author]

The first version is likely to be faster than the second. The first one
just calls string.Concat(string, string, string, string). The second
needs to parse the format string, work out the placeholders and then do
the concatenation.

However, all of this is likely to be dwarfed by the cost of actually
writing to the console. As always, write for readability first and if
you find there's a performance problem, measure, measure, measure!

--
Jon Skeet - <[email protected]>
Web site:http://www.pobox.com/~skeet 
Blog:http://www.msmvps.com/jon_skeet
C# in Depth:http://csharpindepth.com

OK, thank you very much. Just curious, why do they introduce the
second version (the one using String.Format), which is sorta like the
tradtional C syntax of printf?

 

[Stephany Young]

All you have done is considered one of the the most simplistic forms of a
'formatting' overload of the Console.WriteLine method.

Consider:

Console.WriteLine("Employee Name = {0,-30} {1,30}", employee.FirstName,
employee.LastName);

which gives specific alignment the output.

Consider also the myriad of formatting options you have for numeric values.

Try simulating those with simple string concatenation.

The first version is likely to be faster than the second. The first one
just calls string.Concat(string, string, string, string). The second
needs to parse the format string, work out the placeholders and then do
the concatenation.

However, all of this is likely to be dwarfed by the cost of actually
writing to the console. As always, write for readability first and if
you find there's a performance problem, measure, measure, measure!

--
Jon Skeet - <[email protected]>
Web site:http://www.pobox.com/~skeet
Blog:http://www.msmvps.com/jon_skeet
C# in Depth:http://csharpindepth.com

OK, thank you very much. Just curious, why do they introduce the
second version (the one using String.Format), which is sorta like the
tradtional C syntax of printf?